In coil wound motors it is common, after winding to immerse the wound coil into a subsequently cured varnishing liquid thereby impregnating the coil and securing the wires in place. This securing is to ensure that the individual wires do not become loose, noisy, and become subject to early failure through vibration and other movement. Conventional varnishing also improves the wound coil's resistance to moisture, insulates any nicks or scrapes caused in winding, and eliminates direct exposure of the windings to dust, dirt, grease and oil. The state of the art has progressed to the point where it has been found that coil wires useful in this environment can be made with outer coatings which are selfadhering or selfbonding, thus eliminating the need for a separate varnishing step. For example, note U.S. Pat. Nos. 3,553,011; 3,953,649; 3,975,571; 4,163,826; and 4,216,263.
As in other areas, once materials which could be used as selfbondable magnet wires were uncovered, users began to look to wire manufacturers for improved wire properties in this area with a view towards eliminating the varnishing operation entirely,, e.g. for cost purposes. Moisture resistance is a significant consideration. The ability to reliably power insert coils of such magnet wire, is also important. Furthermore, in the area of hermetic motors, a selfbonding magnet wire insulation material which could withstand the rigors of the hermetic motor environment, for example, heat resistance, solvent resistance, etc. has hitherto not been used.
Accordingly, what is needed in this art is a selfbonding magnet with suitable chemical and mechanical properties to provide good moisture resistance, power insertability, and usefulness in a hermetic motor environment.